HORIZON SHIELD

This connector has been deprecated

Superseded by the io.github.ogasurfproject-jpg/horizon-shield listing at https://mcp.horizonshield.dev, which is the URL published in the official MCP registry. The endpoint behind this listing is the same server and stays reachable.

Create AP2 Fairness Attestation

create_ap2_fairness_attestation

このツールは決済を開始・承認・実行しません。資産・通貨・暗号資産の移動も行いません。発行するのは適正価格の証跡だけです。呼び出すたびに公開台帳へ記録を1件追加するため読み取り専用ではありません。 / This tool does not initiate, authorize, or execute any payment, and does not move funds, currency or crypto assets. It only issues a price-fairness attestation. Each call appends one record to the public ledger, so it is not read-only. AP2(Agent Payments Protocol)対応エージェント向けのブリッジ。決済カート(Cart Mandate)に添付できる適正価格の証跡(FairPriceAttestation)を発行する。AP2のMandateは『ユーザーがこの支払いを承認した』ことを検証可能にし、この証跡は『その価格が適正である』ことを検証可能にする。認可の検証と価値の検証、二つは並列レイヤー。quoted_price を渡すと適正レンジ判定(within/above/below)も同梱する。証跡は SHA-256 と公開台帳と verify_url で誰でも再計算検証できる。 / Bridge for AP2 (Agent Payments Protocol) agents: issues a FairPriceAttestation that a shopping or payments agent can attach to a Cart Mandate before asking the user to sign. AP2 mandates make authorization verifiable; this attestation makes value verifiable. Parallel layers. Pass quoted_price for a fair-range verdict (within, above, below). Independently verifiable via SHA-256, a public ledger and a verify_url. Japan construction and renovation pricing, JPY.

Input Schema

TableJSON Schema

Name	Required	Description
`work`	Yes	工事名(例: 外壁塗装 30坪)
`merchant`	No	(任意) 施工業者名。Cart Mandate 例示に反映するだけで判定には使わない。
`quoted_price`	No	(任意) カートに載せる予定の見積額(円, 数値)。渡すと適正レンジとの判定を証跡に同梱する。

Output Schema

TableJSON Schema

Name	Required	Description
`count`	No	How many records matched. 0 means the source was read and nothing matched. It never means the source could not be read, that returns isError: true.
`lookup`	No	ok = the source was read and something matched. absent = the source was read and nothing matched. A source that could NOT be read never appears here: that returns isError: true and makes no claim about what does or does not exist.
`ap2_bridge`	No	AP2との関係(認可の検証 x 価値の検証)
`attestation`	No	証跡本体(subject, integrity)
`source_read`	No	true on every successful result. A failed lookup does not return a result at all, so this is never false, it is declared so a consumer can assert on it.
`did_you_mean`	No	Near matches, when an exact match was not found.
`cart_mandate_example`	No	添付位置の例示(非規範)

TDQS

A4/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description goes beyond annotations by stating each call appends one record to the public ledger, making the tool non-read-only, and clarifying that no funds or assets are moved. This adds meaningful side-effect context beyond the readOnlyHint/idempotentHint flags.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness3/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with key safety and side-effect information, but it repeats the same content in Japanese and English, making it longer than necessary. While bilingual support is useful, several sentences are redundant and could be tightened.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description covers the tool's purpose, side effects, AP2 integration context, optional quoted_price behavior, and verifiability. With an output schema present, return values do not need to be explained. It is sufficiently complete for an agent to understand when and how to invoke it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the baseline is 3. The description adds some value by explaining that quoted_price yields a within/above/below verdict, but this largely duplicates the schema's own parameter description. No major new parameter semantics are introduced.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's specific function: it issues a FairPriceAttestation and explicitly does not initiate or execute payments. It distinguishes itself from siblings like verify_fair_price and get_price_range by focusing on creation of an attestation for AP2 Cart Mandates.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear context: use this tool to create a price-fairness attestation that an AP2 agent can attach to a Cart Mandate before user signing. It does not explicitly name alternatives or exclusion conditions, so it stops short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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TDQS

A4.1/5.0

Disambiguation4/5

Most tools have distinct purposes: audit_estimate for detailed quote diagnosis, get_price_range for typical ranges, preview_reverse_estimate for early-stage direction, verify_fair_price for tamper-evident records. However, audit_estimate, get_price_range, and preview_reverse_estimate overlap in the price-checking domain, and verify_fair_price vs verify_integrity_claim could be confused (both involve SHA-256 verification), though descriptions clarify the opposite postures.

Naming Consistency4/5

Most tools follow a verb_noun pattern (audit_estimate, check_red_flags, get_price_range, list_cost_categories, search_cost_category, suggest_ehn, verify_fair_price). Minor deviations: create_ap2_fairness_attestation is longer and more specific, and get_agent_card/get_estimate_reading_guide/get_fair_price_sources/get_jccdb_dataset_info all start with 'get' but vary in noun phrasing. Overall consistent and predictable.

Tool Count4/5

14 tools is within the ideal 3-15 range, and each tool serves a distinct function in the domain of construction estimate auditing and fair-price verification. Slightly on the higher end but justified by the breadth of features (price lookup, audit, attestation, verification, data sources, educational guides).

Completeness4/5

The server covers the core workflow: lookup price ranges, audit specific quotes, check red flags, generate attestations, verify claims, and access data sources. Minor gaps: no tool for submitting new price data or updating categories, and no direct tool for comparing multiple quotes side-by-side, but agents can work around these with existing tools.

Resources

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